A user environment, such as a residence or an office building, for example, may be configured using various types of load control systems. A lighting control system may be used to control the lighting loads in a user environment. The lighting control system may include various devices, such as input devices and load control devices, capable of communicating via radio frequency (RF) communications. For example, a remote control device may be used to communicate with lighting devices (e.g., light bulbs) in the load control system to control the lighting level of the lighting devices. The devices may communicate in a network using RF communications, such as ZIGBEE® communications; BLUETOOTH® communications; or proprietary communications, such as CLEAR CONNECT™.
In a wireless communications network, the remote control device can control a group of lighting devices using multicast messages. The remote control device may send multicast messages with a group identifier. The lighting devices that are associated with the group identifier will perform lighting control thereon according to the command in the multicast message. The lighting devices will then forward the message to other neighboring lighting devices to identify the group identifier and perform lighting control if associated with the group identifier.
The number of multicast messages sent in the wireless communication network may be limited according to a standard and/or to prevent interference or link saturation on the network. For example, in a ZIGBEE® home automation network, a remote control device may be prevented from controlling lighting devices using more than nine (9) multicast messages over a nine (9) second period of time. If the remote control device exceeds the limit, the lighting devices will lock up for a period of time (e.g., a number of seconds) before allowing control from another message. Thus, the use of multicast messages may have a rate limit, which may cause communications to the lighting devices to be stopped when the rate limit is exceeded, or limiting the lighting levels to be discrete or choppy, which may be undesirable.
In a wireless communications network, the remote control device can alternatively control a group of lighting devices using unicast messages. The remote control device may send independent unicast messages directly to each of the associated lighting devices. Each unicast message may include a unique identifier of the remote control device and a unique identifier of the lighting device for being controlled according to the command in the unicast message. As the unicast messages may be communicated to each lighting device in the group individually, the use of unicast messages for controlling the lighting level of lighting devices in a group may cause each lighting device in the group to turn on, turn off, or adjust the lighting intensity at different times, which may be distracting and undesirable.